By comparison with other patient data generated in clinical laboratories, arterial blood gas results are commonly perceived by students and junior clinical staff to be among the most difficult to understand and interpret. Help is at hand. In a recent, easily comprehended article the authors provide a logical stepwise...

Anemia is a common feature of critical illness and roughly a third of all patients being cared for in intensive care units are given red-cell transfusion. Although such transfusions are unequivocally lifesaving for some patients, e.g. the exsanguinating trauma victim, the benefit is less clear-cut for others.  There...

Hemolysis causes clinically significant bias in four of twelve parameters generated during blood gas analysis. That is the headline finding of a recently published study that is, according to the authors, the first ever to investigate the effect of hemolysis on blood gas analytes. Venous blood was sampled from nine...

Pulse oximeters, which are ubiquitous in nearly all areas of clinical care, provide the means for safe, non-invasive continuous monitoring of blood oxygen saturation. The validity of using pulse oximetry to assess patient blood oxygenation status depends on SpO₂, the parameter measured by pulse oximetry, being a...

The incorporation of CO-oximeters in modern blood gas analyzers allows rapid determination of the amount of carboxyhemoglobin in blood. This, in turn, allows rapid diagnosis of carbon monoxide poisoning, the subject of a recently published review.  This wide-ranging review article begins with consideration of the...

Extracellular (serum) potassium concentration is normally maintained within the approximate reference range of 3.5-5.2 mmol/L; this is important for normal cardiac function. Both reduced serum potassium (hypokalemia) and increased serum potassium (hyperkalemia) can, if sufficiently severe, be associated with...

The calcium present in blood plasma comprises two almost equal fractions: half is bound to albumin and the remainder is unbound, free ionized calcium. Only the free ionized calcium is physiologically active. There are two ways of assessing patient blood calcium status.  The first – at one time the only available...

Arterial blood gas analysis in cases of metabolic acidosis reveals primary decrease in pH and bicarbonate, and secondary (compensatory) reduction in pCO₂. The most common cause of metabolic acidosis is increased production of endogenous metabolic acids, either lactic acid, in which case the condition is called lactic...

The preanalytical phase of laboratory testing has long been recognized as a stage for potential error, and blood gas analysis is a test that is well-recognized as being particularly vulnerable in this regard. Much research has been directed at devising procedures that minimize variability of measured blood gas...

Metabolic acidosis is a common metabolic disturbance among the acutely/critically ill that has many possible causes. The condition is diagnosed by arterial blood gas analysis which reveals primary reduction in pH and bicarbonate, followed by secondary (compensatory) reduction in pCO₂.  Abnormal accumulation of...